Global biogeography of mating system variation in seed plants

Latitudinal gradients in biotic interactions have been suggested as causes of global patterns of biodiversity and phenotypic variation. Plant biologists have long speculated that outcrossing mating systems are more common at low than high latitudes owing to a greater predictability of plant–pollinator interactions in the tropics; however, these ideas have not previously been tested. Here, we present the first global biogeographic analysis of plant mating systems based on 624 published studies from 492 taxa. We found a weak decline in outcrossing rate towards higher latitudes and among some biomes, but no biogeographic patterns in the frequency of self-incompatibility. Incorporating life history and growth form into biogeographic analyses reduced or eliminated the importance of latitude and biome in predicting outcrossing or self-incompatibility. Our results suggest that biogeographic patterns in mating system are more likely a reflection of the frequency of life forms across latitudes rather than the strength of plant–pollinator interactions

Trait correlates and functional significance of heteranthery in flowering plants

Flowering plants display extraordinary diversity in the morphology of male sexual organs, yet the functional significance of this variation is not well understood. Here, we conducted a comparative analysis of floral correlates of heteranthery – the morphological and functional differentiation of anthers within flowers – among angiosperm families to identify traits associated with this condition. • We performed a phylogenetic analysis of correlated evolution between heteranthery and several floral traits commonly reported from heterantherous taxa. In addition, we quantified the effect of phylogenetic uncertainty in the observed patterns of correlated evolution by comparing trees in which polytomous branches were randomly resolved. • Heteranthery is reported from 12 angiosperm orders and is phylogenetically associated with the absence of floral nectaries, buzz-pollination and enantiostyly (mirror-image flowers). These associations are robust to particularities of the underlying phylogenetic hypothesis. • Heteranthery has probably evolved as a result of pollinator-mediated selection and appears to function to reduce the conflict of relying on pollen both as food to attract pollinators and as the agent of male gamete transfer. The relative scarcity of heteranthery among angiosperm families suggests that the conditions permitting its evolution are not easily met despite the abundance of pollen-collecting bees and nectarless flowers

Data from: Evidence for rapid evolutionary change in an invasive plant in response to biological control

We present evidence that populations of an invasive plant species that have become re-associated with a specialist herbivore in the exotic range through biological control have rapidly evolved increased anti-herbivore defences compared to populations not exposed to biocontrol. We grew half-sib families of the invasive plant Lythrum salicaria sourced from 17 populations near Ottawa, Canada, that differed in their history of exposure to a biocontrol agent, the specialist beetle Neogalerucella calmariensis. In a greenhouse experiment, we manipulated larval and adult herbivory to examine whether a population's history of biocontrol influenced plant defence and growth. Plants sourced from populations with a history of biocontrol suffered lower defoliation than naïve, previously unexposed populations, strongly suggesting they had evolved higher resistance. Plants from biocontrol-exposed populations were also larger and produced more branches in response to herbivory, regrew faster even in the absence of herbivory, and were better at compensating for the impacts of herbivory on growth (i.e., they exhibited increased tolerance). Furthermore, resistance and tolerance were positively correlated among genotypes with a history of biocontrol but not among naïve genotypes. Our findings suggest that biocontrol can rapidly select for increased defences in an invasive plant, and may favour a mixed defence strategy of resistance and tolerance without an obvious cost to plant vigour. While rarely studied, such evolutionary responses in the target species have important implications for the long-term efficacy of biocontrol programmes

Unexpected offspring sex ratios in response to habitat quality in a size-dimorphic bark beetle

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Data from: No consistent pollinator-mediated impacts of alien plants on natives

The introduction of an alien plant is widely assumed to have negative consequences for the pollinator-mediated fitness of nearby natives. Indeed, a number of studies, including a highly cited meta-analysis, have concluded that the trend for such interactions is ompetitive. Here we provide evidence that publication bias and study design have obscured our ability to ssess the pollinator-mediated impacts of alien plants. In a meta-analysis of 76 studies, we demonstrate that alien/native status does not predict the outcome of pollinator-mediated interactions among plants. oreover, we found no evidence that similarity in floral traits or phylogenetic distance between species pairs influences the outcome of pollinator-mediated interactions. Instead, we report that aspects of study design, such as distance between the control and nearest neighbour, and/or the arrangement of study plants better predict the impact of a neighbour than does alien/native status. Our study sheds new light on the role that publication bias and experimental design play in the evaluation of key patterns in ecology. We conclude that, due to the absence of clear, generalisable pollinator-mediated impacts of alien species, management schemes should base decisions in community-wide assessments of the impacts of individual alien plant species, and not solely on alien/native status itself

Data from: A phylogenetic analysis of trait convergence in the spring flora

In temperate deciduous forests, spring flowering plants exhibit remarkable similarity in a number of characteristics, including reproductive, vegetative, and ecological traits. The apparent convergence of floral traits, especially corolla colour, among spring flowering species has been well documented, but remains poorly understood. Here we review adaptive hypotheses and predictions that have been proposed to explain the apparent correlation between spring flowering and a suite of traits. We investigated the correlation between flowering phenology (i.e., spring or nonspring) and several key traits using phylogenetic comparative methods. Through this analysis we were able to confirm the existence of a correlation for five of the six traits examined. Specifically, spring flowering is shown to have evolved in a correlated fashion with reproductive schedule (perennial vs. annual), light corolla colour, fruit type, growth form, and forest strata layer. In general, our survey determined that spring flowering species are perennial, have light coloured corollas, a herbaceous growth form, and tend to occupy the understory of the forest. These results are discussed in light of the reviewed adaptive hypotheses and the spring pollination environment

C&S2017.Complete.Data.Set

Source articles, effect sizes & associated variances, and assorted independent variables used to produce the models presented in the article

Hensel and Sargent Botany data

The file contains two worksheets. One sheet contains phenology, fruit type, growth form, forest strata layer, floral colour, and reproductive schedule data for 465 temperate deciduous forest species. The second sheet contains a legend explaining the coding of the character states of the traits. The data was collected from the The New Britton and Brown Illustrated Flora of the Northeastern United States and Adjacent Canada (Gleason 1952) and was used to investigate correlated evolution between flowering phenology and a suite of ecological, reproductive, and vegetative traits